Nuclear magnetic resonance (NMR) spectroscopy has been used to study water protons in normal and malignant tissue. The relaxation times for the water protons are longer for malignant than normal tissue water. This has been observed in a large number of published studies. The reason appears to be a relatively higher state of hydration for tumor tissue which leads to less interaction of water with tissue components. We propose to use 23Na ion NMR spectroscopy to study the state of Na ion in normal and malignant tissues. Based on previous water proton studies, we believe that differences in 23Na resonances will also be observed. The sodium nucleus is quadrupolar and, therefore, should interact strongly with its environment. In order to understand the resonance phenomena in heterogeneous systems we have been studying 23Na ion in dispersions of red blood cells and bacteria. The studies are now beginning on normal and malignant tissues.